Background:Nitrogen(N)deposition affects forest stoichiometric flexibility through changing soil nutrient availability to influence plant uptake.However,the effect of N deposition on the flexibility of carbon(C),N,and...Background:Nitrogen(N)deposition affects forest stoichiometric flexibility through changing soil nutrient availability to influence plant uptake.However,the effect of N deposition on the flexibility of carbon(C),N,and phosphorus(P)in forest plant-soil-microbe systems remains unclear.Methods:We conducted a meta-analysis based on 751 pairs of observations to evaluate the responses of plant,soil and microbial biomass C,N and P nutrients and stoichiometry to N addition in different N intensity(050,50–100,>100 kg·ha^(-1)·year^(-1)of N),duration(0–5,>5 year),method(understory,canopy),and matter(ammonium N,nitrate N,organic N,mixed N).Results:N addition significantly increased plant N:P(leaf:14.98%,root:13.29%),plant C:P(leaf:6.8%,root:25.44%),soil N:P(13.94%),soil C:P(10.86%),microbial biomass N:P(23.58%),microbial biomass C:P(12.62%),but reduced plant C:N(leaf:6.49%,root:9.02%).Furthermore,plant C:N:P stoichiometry changed significantly under short-term N inputs,while soil and microorganisms changed drastically under high N addition.Canopy N addition primarily affected plant C:N:P stoichiometry through altering plant N content,while understory N inputs altered more by influencing soil C and P content.Organic N significantly influenced plant and soil C:N and C:P,while ammonia N changed plant N:P.Plant C:P and soil C:N were strongly correlated with mean annual precipitation(MAT),and the C:N:P stoichiometric flexibility in soil and plant under N addition connected with soil depth.Besides,N addition decoupled the correlations between soil microorganisms and the plant.Conclusions:N addition significantly increased the C:P and N:P in soil,plant,and microbial biomass,reducing plant C:N,and aggravated forest P limitations.Significantly,these impacts were contingent on climate types,soil layers,and N input forms.The findings enhance our comprehension of the plant-soil system nutrient cycling mechanisms in forest ecosystems and plant strategy responses to N deposition.展开更多
Friction stir welding [FSW） has achieved remarkable success in the joining and processing of aluminium alloys and other softer structural alloys. Conventional FSW, however, has not been entirely successful in the joi...Friction stir welding [FSW） has achieved remarkable success in the joining and processing of aluminium alloys and other softer structural alloys. Conventional FSW, however, has not been entirely successful in the joining, processing and manufacturing of different desired materials essential to meet the sophis- ticated green globe requirements. Through the efforts of improving the process and transferring the existing friction stir knowledge base to other advanced applications, several friction stir based daughter technologies have emerged over the timeline, A few among these technologies are well developed while others are under the process of emergence. Beginning with a broad classification of the scattered fric- tions stir based technologies into two categories, welding and processing, it appears now time to know, compile and review these to enable their rapid access for reference and academia. In this review article, the friction stir based technologies classified under the categol^J of welding are those applied for join- ing of materials while the remnant are labeled as friction stir processing （FSP） technologies. This review article presents an overview of four general aspects of both the developed and the developing friction stir based technologies, their associated process parameters, metallurgical features of their products and their feasibility and application to various materials. The lesser known and emerging technologies have been emphasized.展开更多
The undesired side reactions at electrode/electrolyte interface as well as the irreversible phase evolution during electrochemical cycling significantly affect the cyclic performances of nickel-rich NMCs electrode mat...The undesired side reactions at electrode/electrolyte interface as well as the irreversible phase evolution during electrochemical cycling significantly affect the cyclic performances of nickel-rich NMCs electrode materials.Electrolyte optimization is an effective approach to suppress such an adverse side reaction,thereby enhancing the electrochemical properties.Herein,a novel boron-based film forming additive,tris(2,2,2-trifluoroethyl)borate(TTFEB),has been introduced to regulate the interphasial chemistry of LiNi0.8Mn0.1Co0.1O2(NMC811)cathode to improve its long-term cyclability and rate properties.The results of multi-model diagnostic study reveal that formation lithium fluoride(LiF)-rich and boron(B)containing cathode electrolyte interphase(CEI)not only stabilizes cathode surface,but also prevents electrolyte decomposition.Moreover,homogenously distributed B containing species serves as a skeleton to form more uniform and denser CEI,reducing the interphasial resistance.Remarkably,the Li/NMC811 cell with the TTFEB additive delivers an exceptional cycling stability with a high-capacity retention of 72.8%after 350 electrochemical cycles at a 1 C current rate,which is significantly higher than that of the cell cycled in the conventional electrolyte(59.7%).These findings provide a feasible pathway for improving the electrochemical performance of Ni-rich NMCs cathode by regulating the interphasial chemistry.展开更多
Let f（X） be an additive form defined by f（X）=f（x<sub>1</sub>. x<sub>2</sub>,…,x<sub>s</sub>）=σ<sub>1</sub>α<sub>1</sub>x<sub>1</sub><...Let f（X） be an additive form defined by f（X）=f（x<sub>1</sub>. x<sub>2</sub>,…,x<sub>s</sub>）=σ<sub>1</sub>α<sub>1</sub>x<sub>1</sub><sup>k</sup>+σ<sub>α</sub><sub>2</sub>x<sub>2</sub><sup>k</sup>+…+σ<sub>s</sub>α<sub>s</sub>x<sub>s</sub><sup>k</sup>, where α<sub>o</sub>≠0 is integer, i=1, 2,…, s. In 1979, Schmidt proved that if ε】0 then there is a large constant C（k, ε） such that for s≥C（k, ε） the equation f（X）=0 has a nontrivial integer solution in σ<sub>1</sub>. σ<sub>2</sub>,…σ<sub>s</sub>, x<sub>1</sub>, x<sub>2</sub>…,x<sub>s</sub> satisfying σ<sub>i</sub>=±1 and |x<sub>i</sub>|≤A<sup>ε</sup>, i=1, 2.…,s where A=max|ai|. Schmidt did not estimate this constant C（k. ε） since it would be extremely large. In this paper, we prove the following result: Theorem 1 If log A≤1/ε,then C（k,ε）≤max （2/ε,20）; if log A】1/ε,A is sufficiently larye and 1/2A≤5≤|a<sub>i</sub>|≤A,i=1. 2,…, s, then C（k,ε）≤c<sub>1</sub>c<sub>2</sub><sup>p</sup> and if the last condition is omitted, then C（k. ε）≤[4/ε]c<sub>1</sub>c<sub>2</sub>,where c<sub>1</sub>={2k+1 for≤k≤11 [5k<sup>2</sup>log k] for k≥12, c<sub>2</sub>=100c<sub>1</sub>k<sup>2</sup>2<sup>k</sup>+c<sub>1</sub><sup>2</sup> and p=2[log 2c<sub>1</sub>/ε]. We note that the inequality in the first case is sharp but not in the second case.展开更多
基金supported by the National Natural Science Foundation of China(Nos.31800369,32271686,U1904204)the State Scholarship Fund of Chinathe Innovation Scientists and Technicians Troop Construction Projects of Henan Province(No.182101510005)。
文摘Background:Nitrogen(N)deposition affects forest stoichiometric flexibility through changing soil nutrient availability to influence plant uptake.However,the effect of N deposition on the flexibility of carbon(C),N,and phosphorus(P)in forest plant-soil-microbe systems remains unclear.Methods:We conducted a meta-analysis based on 751 pairs of observations to evaluate the responses of plant,soil and microbial biomass C,N and P nutrients and stoichiometry to N addition in different N intensity(050,50–100,>100 kg·ha^(-1)·year^(-1)of N),duration(0–5,>5 year),method(understory,canopy),and matter(ammonium N,nitrate N,organic N,mixed N).Results:N addition significantly increased plant N:P(leaf:14.98%,root:13.29%),plant C:P(leaf:6.8%,root:25.44%),soil N:P(13.94%),soil C:P(10.86%),microbial biomass N:P(23.58%),microbial biomass C:P(12.62%),but reduced plant C:N(leaf:6.49%,root:9.02%).Furthermore,plant C:N:P stoichiometry changed significantly under short-term N inputs,while soil and microorganisms changed drastically under high N addition.Canopy N addition primarily affected plant C:N:P stoichiometry through altering plant N content,while understory N inputs altered more by influencing soil C and P content.Organic N significantly influenced plant and soil C:N and C:P,while ammonia N changed plant N:P.Plant C:P and soil C:N were strongly correlated with mean annual precipitation(MAT),and the C:N:P stoichiometric flexibility in soil and plant under N addition connected with soil depth.Besides,N addition decoupled the correlations between soil microorganisms and the plant.Conclusions:N addition significantly increased the C:P and N:P in soil,plant,and microbial biomass,reducing plant C:N,and aggravated forest P limitations.Significantly,these impacts were contingent on climate types,soil layers,and N input forms.The findings enhance our comprehension of the plant-soil system nutrient cycling mechanisms in forest ecosystems and plant strategy responses to N deposition.
基金financial support on this work from the National Natural Science Foundation of China(Grant Nos.51475272 and 51550110501)Shandong University for the Postdoctoral fellowship
文摘Friction stir welding [FSW） has achieved remarkable success in the joining and processing of aluminium alloys and other softer structural alloys. Conventional FSW, however, has not been entirely successful in the joining, processing and manufacturing of different desired materials essential to meet the sophis- ticated green globe requirements. Through the efforts of improving the process and transferring the existing friction stir knowledge base to other advanced applications, several friction stir based daughter technologies have emerged over the timeline, A few among these technologies are well developed while others are under the process of emergence. Beginning with a broad classification of the scattered fric- tions stir based technologies into two categories, welding and processing, it appears now time to know, compile and review these to enable their rapid access for reference and academia. In this review article, the friction stir based technologies classified under the categol^J of welding are those applied for join- ing of materials while the remnant are labeled as friction stir processing （FSP） technologies. This review article presents an overview of four general aspects of both the developed and the developing friction stir based technologies, their associated process parameters, metallurgical features of their products and their feasibility and application to various materials. The lesser known and emerging technologies have been emphasized.
基金supported by the National Natural Science Foundation of China(Grant No.22209106).
文摘The undesired side reactions at electrode/electrolyte interface as well as the irreversible phase evolution during electrochemical cycling significantly affect the cyclic performances of nickel-rich NMCs electrode materials.Electrolyte optimization is an effective approach to suppress such an adverse side reaction,thereby enhancing the electrochemical properties.Herein,a novel boron-based film forming additive,tris(2,2,2-trifluoroethyl)borate(TTFEB),has been introduced to regulate the interphasial chemistry of LiNi0.8Mn0.1Co0.1O2(NMC811)cathode to improve its long-term cyclability and rate properties.The results of multi-model diagnostic study reveal that formation lithium fluoride(LiF)-rich and boron(B)containing cathode electrolyte interphase(CEI)not only stabilizes cathode surface,but also prevents electrolyte decomposition.Moreover,homogenously distributed B containing species serves as a skeleton to form more uniform and denser CEI,reducing the interphasial resistance.Remarkably,the Li/NMC811 cell with the TTFEB additive delivers an exceptional cycling stability with a high-capacity retention of 72.8%after 350 electrochemical cycles at a 1 C current rate,which is significantly higher than that of the cell cycled in the conventional electrolyte(59.7%).These findings provide a feasible pathway for improving the electrochemical performance of Ni-rich NMCs cathode by regulating the interphasial chemistry.
文摘Let f（X） be an additive form defined by f（X）=f（x<sub>1</sub>. x<sub>2</sub>,…,x<sub>s</sub>）=σ<sub>1</sub>α<sub>1</sub>x<sub>1</sub><sup>k</sup>+σ<sub>α</sub><sub>2</sub>x<sub>2</sub><sup>k</sup>+…+σ<sub>s</sub>α<sub>s</sub>x<sub>s</sub><sup>k</sup>, where α<sub>o</sub>≠0 is integer, i=1, 2,…, s. In 1979, Schmidt proved that if ε】0 then there is a large constant C（k, ε） such that for s≥C（k, ε） the equation f（X）=0 has a nontrivial integer solution in σ<sub>1</sub>. σ<sub>2</sub>,…σ<sub>s</sub>, x<sub>1</sub>, x<sub>2</sub>…,x<sub>s</sub> satisfying σ<sub>i</sub>=±1 and |x<sub>i</sub>|≤A<sup>ε</sup>, i=1, 2.…,s where A=max|ai|. Schmidt did not estimate this constant C（k. ε） since it would be extremely large. In this paper, we prove the following result: Theorem 1 If log A≤1/ε,then C（k,ε）≤max （2/ε,20）; if log A】1/ε,A is sufficiently larye and 1/2A≤5≤|a<sub>i</sub>|≤A,i=1. 2,…, s, then C（k,ε）≤c<sub>1</sub>c<sub>2</sub><sup>p</sup> and if the last condition is omitted, then C（k. ε）≤[4/ε]c<sub>1</sub>c<sub>2</sub>,where c<sub>1</sub>={2k+1 for≤k≤11 [5k<sup>2</sup>log k] for k≥12, c<sub>2</sub>=100c<sub>1</sub>k<sup>2</sup>2<sup>k</sup>+c<sub>1</sub><sup>2</sup> and p=2[log 2c<sub>1</sub>/ε]. We note that the inequality in the first case is sharp but not in the second case.
